<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>return</title>
</head>
<body>

<script src="../jquery-1.7.2.js"></script>

<script>
    $(function(){
        b = 2;
        var a = 1 ;
        function call(a){
            return a
        }
        function  tell(b){
            return b+1
        }
    console.log(call(a));//调用外部变量
    console.log(call());//运行变量
    console.log(call(b));//调用全局变量
    console.log(tell(b));//调用并修改全局变量
    })
</script>
</html>
